Learn on PengiIllustrative Mathematics, Grade 5Chapter 3: Multiplying and Dividing Fractions

Lesson 13: Fraction Games

In this Grade 5 Illustrative Mathematics lesson, students apply their understanding of multiplying and dividing fractions — including unit fractions divided by whole numbers and whole numbers divided by unit fractions — to strategically build expressions with the greatest or smallest possible value. Using a set of given digits, learners analyze how the size of factors, dividends, and divisors affects products and quotients (standards 5.NF.B.4, 5.NF.B.6, 5.NF.B.7). The lesson also develops estimation strategies for products involving fractions and mixed numbers.

Section 1

Creating Largest and Smallest Quotients

Property

To create the largest possible quotient from a set of numbers for the expression W÷1dW \div \frac{1}{d}:

  • Use the largest available number for the whole number dividend (WW).
  • Use the next largest available number for the denominator of the unit fraction divisor (dd).

To create the smallest possible quotient:

  • Use the smallest available number for the whole number dividend (WW).
  • Use the next smallest available number for the denominator of the unit fraction divisor (dd).

Examples

Given the numbers 3, 4, and 5 to fill in the blanks for W÷1dW \div \frac{1}{d}:

  • To make the largest quotient: Use the largest number (5) for WW and the next largest (4) for dd.
5÷14=205 \div \frac{1}{4} = 20
  • To make the smallest quotient: Use the smallest number (3) for WW and the next smallest (4) for dd.
3÷14=123 \div \frac{1}{4} = 12

Explanation

This skill challenges you to use your understanding of division to create expressions with the greatest or least possible value. To get the largest result when dividing a whole number by a unit fraction, you need to start with the largest whole number and divide it into the smallest possible fractional pieces. Smaller fractional pieces have larger denominators. To get the smallest result, you should start with the smallest whole number and divide it into the largest possible fractional pieces (which have smaller denominators).

Lesson overview

Expand to review the lesson summary and core properties.

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Section 1

Creating Largest and Smallest Quotients

Property

To create the largest possible quotient from a set of numbers for the expression W÷1dW \div \frac{1}{d}:

  • Use the largest available number for the whole number dividend (WW).
  • Use the next largest available number for the denominator of the unit fraction divisor (dd).

To create the smallest possible quotient:

  • Use the smallest available number for the whole number dividend (WW).
  • Use the next smallest available number for the denominator of the unit fraction divisor (dd).

Examples

Given the numbers 3, 4, and 5 to fill in the blanks for W÷1dW \div \frac{1}{d}:

  • To make the largest quotient: Use the largest number (5) for WW and the next largest (4) for dd.
5÷14=205 \div \frac{1}{4} = 20
  • To make the smallest quotient: Use the smallest number (3) for WW and the next smallest (4) for dd.
3÷14=123 \div \frac{1}{4} = 12

Explanation

This skill challenges you to use your understanding of division to create expressions with the greatest or least possible value. To get the largest result when dividing a whole number by a unit fraction, you need to start with the largest whole number and divide it into the smallest possible fractional pieces. Smaller fractional pieces have larger denominators. To get the smallest result, you should start with the smallest whole number and divide it into the largest possible fractional pieces (which have smaller denominators).